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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rw_lock_generic.h"
#include "condition_variable_wrapper.h"
#include "critical_section_wrapper.h"
namespace webrtc {
RWLockWrapperGeneric::RWLockWrapperGeneric()
: _readersActive(0),
_writerActive(false),
_readersWaiting(0),
_writersWaiting(0)
{
_critSectPtr = CriticalSectionWrapper::CreateCriticalSection();
_readCondPtr = ConditionVariableWrapper::CreateConditionVariable();
_writeCondPtr = ConditionVariableWrapper::CreateConditionVariable();
}
RWLockWrapperGeneric::~RWLockWrapperGeneric()
{
delete _writeCondPtr;
delete _readCondPtr;
delete _critSectPtr;
}
int RWLockWrapperGeneric::Init()
{
return 0;
}
void RWLockWrapperGeneric::AcquireLockExclusive()
{
_critSectPtr->Enter();
if (_writerActive || _readersActive > 0)
{
++_writersWaiting;
while (_writerActive || _readersActive > 0)
{
_writeCondPtr->SleepCS(*_critSectPtr);
}
--_writersWaiting;
}
_writerActive = true;
_critSectPtr->Leave();
}
void RWLockWrapperGeneric::ReleaseLockExclusive()
{
_critSectPtr->Enter();
_writerActive = false;
if (_writersWaiting > 0)
{
_writeCondPtr->Wake();
}else if (_readersWaiting > 0)
{
_readCondPtr->WakeAll();
}
_critSectPtr->Leave();
}
void RWLockWrapperGeneric::AcquireLockShared()
{
_critSectPtr->Enter();
if (_writerActive || _writersWaiting > 0)
{
++_readersWaiting;
while (_writerActive || _writersWaiting > 0)
{
_readCondPtr->SleepCS(*_critSectPtr);
}
--_readersWaiting;
}
++_readersActive;
_critSectPtr->Leave();
}
void RWLockWrapperGeneric::ReleaseLockShared()
{
_critSectPtr->Enter();
--_readersActive;
if (_readersActive == 0 && _writersWaiting > 0)
{
_writeCondPtr->Wake();
}
_critSectPtr->Leave();
}
} // namespace webrtc
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